1. Field of the Invention
The present invention relates to a honeycomb structure. More particularly, it relates to a honeycomb structure which can be used as a catalyst carrier and also functions as a heater when a voltage is applied thereto and further, which has excellent heat shock resisting properties.
2. Description of Related Art
Heretofore, a product in which a catalyst is loaded onto a honeycomb structure made of cordierite has been used for a treatment of harmful substances in an exhaust gas discharged from a car engine. Furthermore, a honeycomb structure formed from a sintered silicon carbide body has been used for purification of the exhaust gas.
When the exhaust gas is treated by the catalyst loaded onto the honeycomb structure, it is necessary to raise a temperature of the catalyst to a predetermined temperature. However, the catalyst temperature is low at start of the engine, which has caused a problem that the exhaust gas is not sufficiently purified.
Consequently, there has been investigated a catalyst converter including a catalyst carrier to be heated by energization and electrodes, and the catalyst carrier is formed from a plurality of segments arranged in a direction perpendicular to a straight line connecting centers of each electrode to each other (e.g., see Patent Document 1). In the catalyst converter, volume resistivities of the plurality of segments are varied, respectively, whereby an amount of heat to be generated by the energization is approximate to a uniform amount.
Furthermore, there has been suggested a honeycomb structure body including a plurality of sintered conductive segment portions each having a honeycomb structure, and a sintered bonding material portion which bonds the sintered conductive segment portions to one another (e.g., see Patent Document 2).    [Patent Document 1] JP-A-2012-188958    [Patent Document 2] JP-A-2011-98866